LibWeb+LibWebSocket: DOM WebSocket subprotocol support

This adds support for WebSocket subprotocols to WebSocket DOM
objects, with some necessary plumbing to LibWebSocket and its
clients.

See the associated pull request for how this was tested.

Ladybird/WebSocketClientManagerLadybird.cpp

@@ -19,10 +19,11 @@ NonnullRefPtr<WebSocketClientManagerLadybird> WebSocketClientManagerLadybird::cr
 WebSocketClientManagerLadybird::WebSocketClientManagerLadybird() = default;
 WebSocketClientManagerLadybird::~WebSocketClientManagerLadybird() = default;
 
-RefPtr<Web::WebSockets::WebSocketClientSocket> WebSocketClientManagerLadybird::connect(AK::URL const& url, DeprecatedString const& origin)
+RefPtr<Web::WebSockets::WebSocketClientSocket> WebSocketClientManagerLadybird::connect(AK::URL const& url, DeprecatedString const& origin, Vector<DeprecatedString> const& protocols)
 {
     WebSocket::ConnectionInfo connection_info(url);
     connection_info.set_origin(origin);
+    connection_info.set_protocols(protocols);
 
     auto impl = adopt_ref(*new WebSocketImplQt);
     auto web_socket = WebSocket::WebSocket::create(move(connection_info), move(impl));

Ladybird/WebSocketClientManagerLadybird.h

@@ -19,7 +19,7 @@ public:
     static NonnullRefPtr<WebSocketClientManagerLadybird> create();
 
     virtual ~WebSocketClientManagerLadybird() override;
-    virtual RefPtr<Web::WebSockets::WebSocketClientSocket> connect(AK::URL const&, DeprecatedString const& origin) override;
+    virtual RefPtr<Web::WebSockets::WebSocketClientSocket> connect(AK::URL const&, DeprecatedString const& origin, Vector<DeprecatedString> const& protocols) override;
 
 private:
     WebSocketClientManagerLadybird();

Ladybird/WebSocketLadybird.cpp

@@ -74,6 +74,11 @@ Web::WebSockets::WebSocket::ReadyState WebSocketLadybird::ready_state()
     VERIFY_NOT_REACHED();
 }
 
+DeprecatedString WebSocketLadybird::subprotocol_in_use()
+{
+    return m_websocket->subprotocol_in_use();
+}
+
 void WebSocketLadybird::send(ByteBuffer binary_or_text_message, bool is_text)
 {
     m_websocket->send(WebSocket::Message(binary_or_text_message, is_text));

Ladybird/WebSocketLadybird.h

@@ -21,6 +21,7 @@ public:
     virtual ~WebSocketLadybird() override;
 
     virtual Web::WebSockets::WebSocket::ReadyState ready_state() override;
+    virtual DeprecatedString subprotocol_in_use() override;
     virtual void send(ByteBuffer binary_or_text_message, bool is_text) override;
     virtual void send(StringView message) override;
     virtual void close(u16 code, DeprecatedString reason) override;

Userland/Libraries/LibProtocol/WebSocket.cpp

@@ -20,6 +20,11 @@ WebSocket::ReadyState WebSocket::ready_state()
     return (WebSocket::ReadyState)m_client->ready_state({}, *this);
 }
 
+DeprecatedString WebSocket::subprotocol_in_use()
+{
+    return m_client->subprotocol_in_use({}, *this);
+}
+
 void WebSocket::send(ByteBuffer binary_or_text_message, bool is_text)
 {
     m_client->send({}, *this, move(binary_or_text_message), is_text);

Userland/Libraries/LibProtocol/WebSocket.h

@@ -53,6 +53,8 @@ public:
 
     ReadyState ready_state();
 
+    DeprecatedString subprotocol_in_use();
+
     void send(ByteBuffer binary_or_text_message, bool is_text);
     void send(StringView text_message);
     void close(u16 code = 1005, DeprecatedString reason = {});

Userland/Libraries/LibProtocol/WebSocketClient.cpp

@@ -34,6 +34,13 @@ u32 WebSocketClient::ready_state(Badge<WebSocket>, WebSocket& connection)
     return IPCProxy::ready_state(connection.id());
 }
 
+DeprecatedString WebSocketClient::subprotocol_in_use(Badge<WebSocket>, WebSocket& connection)
+{
+    if (!m_connections.contains(connection.id()))
+        return DeprecatedString::empty();
+    return IPCProxy::subprotocol_in_use(connection.id());
+}
+
 void WebSocketClient::send(Badge<WebSocket>, WebSocket& connection, ByteBuffer data, bool is_text)
 {
     if (!m_connections.contains(connection.id()))

Userland/Libraries/LibProtocol/WebSocketClient.h

@@ -24,6 +24,7 @@ public:
     RefPtr<WebSocket> connect(const URL&, DeprecatedString const& origin = {}, Vector<DeprecatedString> const& protocols = {}, Vector<DeprecatedString> const& extensions = {}, HashMap<DeprecatedString, DeprecatedString> const& request_headers = {});
 
     u32 ready_state(Badge<WebSocket>, WebSocket&);
+    DeprecatedString subprotocol_in_use(Badge<WebSocket>, WebSocket&);
     void send(Badge<WebSocket>, WebSocket&, ByteBuffer, bool is_text);
     void close(Badge<WebSocket>, WebSocket&, u16 code, DeprecatedString reason);
     bool set_certificate(Badge<WebSocket>, WebSocket&, DeprecatedString, DeprecatedString);

Userland/Libraries/LibWeb/WebSockets/WebSocket.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/QuickSort.h>
 #include <LibJS/Runtime/ArrayBuffer.h>
 #include <LibJS/Runtime/FunctionObject.h>
 #include <LibWeb/DOM/Document.h>
@@ -45,7 +46,7 @@ WebSocketClientSocket::~WebSocketClientSocket() = default;
 WebSocketClientManager::WebSocketClientManager() = default;
 
 // https://websockets.spec.whatwg.org/#dom-websocket-websocket
-WebIDL::ExceptionOr<JS::NonnullGCPtr<WebSocket>> WebSocket::construct_impl(JS::Realm& realm, DeprecatedString const& url)
+WebIDL::ExceptionOr<JS::NonnullGCPtr<WebSocket>> WebSocket::construct_impl(JS::Realm& realm, DeprecatedString const& url, Optional<Variant<DeprecatedString, Vector<DeprecatedString>>> const& protocols)
 {
     auto& window = verify_cast<HTML::Window>(realm.global_object());
     AK::URL url_record(url);
@@ -55,18 +56,39 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<WebSocket>> WebSocket::construct_impl(JS::R
         return WebIDL::SyntaxError::create(realm, "Invalid protocol");
     if (!url_record.fragment().is_empty())
         return WebIDL::SyntaxError::create(realm, "Presence of URL fragment is invalid");
-    // 5. If `protocols` is a string, set `protocols` to a sequence consisting of just that string
+    Vector<DeprecatedString> protocols_sequence;
-    // 6. If any of the values in `protocols` occur more than once or otherwise fail to match the requirements, throw SyntaxError
+    if (protocols.has_value()) {
-    return MUST_OR_THROW_OOM(realm.heap().allocate<WebSocket>(realm, window, url_record));
+        // 5. If `protocols` is a string, set `protocols` to a sequence consisting of just that string
+        if (protocols.value().has<DeprecatedString>())
+            protocols_sequence = { protocols.value().get<DeprecatedString>() };
+        else
+            protocols_sequence = protocols.value().get<Vector<DeprecatedString>>();
+        // 6. If any of the values in `protocols` occur more than once or otherwise fail to match the requirements, throw SyntaxError
+        auto sorted_protocols = protocols_sequence;
+        quick_sort(sorted_protocols);
+        for (size_t i = 0; i < sorted_protocols.size(); i++) {
+            // https://datatracker.ietf.org/doc/html/rfc6455
+            // The elements that comprise this value MUST be non-empty strings with characters in the range U+0021 to U+007E not including
+            // separator characters as defined in [RFC2616] and MUST all be unique strings.
+            auto protocol = sorted_protocols[i];
+            if (i < sorted_protocols.size() - 1 && protocol == sorted_protocols[i + 1])
+                return WebIDL::SyntaxError::create(realm, "Found a duplicate protocol name in the specified list");
+            for (auto character : protocol) {
+                if (character < '\x21' || character > '\x7E')
+                    return WebIDL::SyntaxError::create(realm, "Found invalid character in subprotocol name");
+            }
+        }
+    }
+    return MUST_OR_THROW_OOM(realm.heap().allocate<WebSocket>(realm, window, url_record, protocols_sequence));
 }
 
-WebSocket::WebSocket(HTML::Window& window, AK::URL& url)
+WebSocket::WebSocket(HTML::Window& window, AK::URL& url, Vector<DeprecatedString> const& protocols)
     : EventTarget(window.realm())
     , m_window(window)
 {
     // FIXME: Integrate properly with FETCH as per https://fetch.spec.whatwg.org/#websocket-opening-handshake
     auto origin_string = m_window->associated_document().origin().serialize();
-    m_websocket = WebSocketClientManager::the().connect(url, origin_string);
+    m_websocket = WebSocketClientManager::the().connect(url, origin_string, protocols);
     m_websocket->on_open = [weak_this = make_weak_ptr<WebSocket>()] {
         if (!weak_this)
             return;
@@ -132,9 +154,7 @@ DeprecatedString WebSocket::protocol() const
 {
     if (!m_websocket)
         return DeprecatedString::empty();
-    // https://websockets.spec.whatwg.org/#feedback-from-the-protocol
+    return m_websocket->subprotocol_in_use();
-    // FIXME: Change the protocol attribute's value to the subprotocol in use, if it is not the null value.
-    return DeprecatedString::empty();
 }
 
 // https://websockets.spec.whatwg.org/#dom-websocket-close

Userland/Libraries/LibWeb/WebSockets/WebSocket.h

@@ -37,7 +37,7 @@ public:
         Closed = 3,
     };
 
-    static WebIDL::ExceptionOr<JS::NonnullGCPtr<WebSocket>> construct_impl(JS::Realm&, DeprecatedString const& url);
+    static WebIDL::ExceptionOr<JS::NonnullGCPtr<WebSocket>> construct_impl(JS::Realm&, DeprecatedString const& url, Optional<Variant<DeprecatedString, Vector<DeprecatedString>>> const& protocols);
 
     virtual ~WebSocket() override;
 
@@ -66,7 +66,7 @@ private:
     void on_error();
     void on_close(u16 code, DeprecatedString reason, bool was_clean);
 
-    WebSocket(HTML::Window&, AK::URL&);
+    WebSocket(HTML::Window&, AK::URL&, Vector<DeprecatedString> const& protocols);
 
     virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
@@ -99,6 +99,7 @@ public:
     };
 
     virtual Web::WebSockets::WebSocket::ReadyState ready_state() = 0;
+    virtual DeprecatedString subprotocol_in_use() = 0;
 
     virtual void send(ByteBuffer binary_or_text_message, bool is_text) = 0;
     virtual void send(StringView text_message) = 0;
@@ -120,7 +121,7 @@ public:
     static void initialize(RefPtr<WebSocketClientManager>);
     static WebSocketClientManager& the();
 
-    virtual RefPtr<WebSocketClientSocket> connect(AK::URL const&, DeprecatedString const& origin) = 0;
+    virtual RefPtr<WebSocketClientSocket> connect(AK::URL const&, DeprecatedString const& origin, Vector<DeprecatedString> const& protocols) = 0;
 
 protected:
     explicit WebSocketClientManager();

Userland/Libraries/LibWeb/WebSockets/WebSocket.idl

@@ -5,8 +5,7 @@
 [Exposed=(Window,Worker)]
 interface WebSocket : EventTarget {
 
-    // FIXME: A second "protocols" argument should be added once supported
+    constructor(USVString url, optional (DOMString or sequence<DOMString>) protocols);
-    constructor(USVString url);
 
     readonly attribute USVString url;
 

Userland/Libraries/LibWebSocket/WebSocket.cpp

@@ -74,6 +74,11 @@ ReadyState WebSocket::ready_state()
     }
 }
 
+DeprecatedString WebSocket::subprotocol_in_use()
+{
+    return m_subprotocol_in_use;
+}
+
 void WebSocket::send(Message const& message)
 {
     // Calling send on a socket that is not opened is not allowed
@@ -356,22 +361,21 @@ void WebSocket::read_server_handshake()
         }
 
         if (header_name.equals_ignoring_case("Sec-WebSocket-Protocol"sv)) {
-            // 6. |Sec-WebSocket-Protocol| should not contain an extension that doesn't appear in m_connection->protocols()
+            // 6. If the response includes a |Sec-WebSocket-Protocol| header field and this header field indicates the use of a subprotocol that was not present in the client's handshake (the server has indicated a subprotocol not requested by the client), the client MUST _Fail the WebSocket Connection_.
-            auto server_protocols = parts[1].split(',');
+            // Additionally, Section 4.2.2 says this is "Either a single value representing the subprotocol the server is ready to use or null."
-            for (auto const& protocol : server_protocols) {
+            auto server_protocol = parts[1].trim_whitespace();
-                auto trimmed_protocol = protocol.trim_whitespace();
+            bool found_protocol = false;
-                bool found_protocol = false;
+            for (auto const& supported_protocol : m_connection.protocols()) {
-                for (auto const& supported_protocol : m_connection.protocols()) {
+                if (server_protocol.equals_ignoring_case(supported_protocol)) {
-                    if (trimmed_protocol.equals_ignoring_case(supported_protocol)) {
+                    found_protocol = true;
-                        found_protocol = true;
-                    }
-                }
-                if (!found_protocol) {
-                    dbgln("WebSocket: Server HTTP Handshake Header |Sec-WebSocket-Protocol| contains '{}', which is not supported by the client. Failing connection.", trimmed_protocol);
-                    fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
-                    return;
                 }
             }
+            if (!found_protocol) {
+                dbgln("WebSocket: Server HTTP Handshake Header |Sec-WebSocket-Protocol| contains '{}', which is not supported by the client. Failing connection.", server_protocol);
+                fatal_error(WebSocket::Error::ConnectionUpgradeFailed);
+                return;
+            }
+            m_subprotocol_in_use = server_protocol;
             continue;
         }
     }

Userland/Libraries/LibWebSocket/WebSocket.h

@@ -32,6 +32,8 @@ public:
 
     ReadyState ready_state();
 
+    DeprecatedString subprotocol_in_use();
+
     // Call this to start the WebSocket connection.
     void start();
 
@@ -95,6 +97,8 @@ private:
 
     InternalState m_state { InternalState::NotStarted };
 
+    DeprecatedString m_subprotocol_in_use { DeprecatedString::empty() };
+
     DeprecatedString m_websocket_key;
     bool m_has_read_server_handshake_first_line { false };
     bool m_has_read_server_handshake_upgrade { false };

Userland/Libraries/LibWebView/WebSocketClientAdapter.cpp

@@ -87,6 +87,11 @@ Web::WebSockets::WebSocket::ReadyState WebSocketClientSocketAdapter::ready_state
     VERIFY_NOT_REACHED();
 }
 
+DeprecatedString WebSocketClientSocketAdapter::subprotocol_in_use()
+{
+    return m_websocket->subprotocol_in_use();
+}
+
 void WebSocketClientSocketAdapter::send(ByteBuffer binary_or_text_message, bool is_text)
 {
     m_websocket->send(binary_or_text_message, is_text);
@@ -115,9 +120,9 @@ WebSocketClientManagerAdapter::WebSocketClientManagerAdapter(NonnullRefPtr<Proto
 
 WebSocketClientManagerAdapter::~WebSocketClientManagerAdapter() = default;
 
-RefPtr<Web::WebSockets::WebSocketClientSocket> WebSocketClientManagerAdapter::connect(const AK::URL& url, DeprecatedString const& origin)
+RefPtr<Web::WebSockets::WebSocketClientSocket> WebSocketClientManagerAdapter::connect(const AK::URL& url, DeprecatedString const& origin, Vector<DeprecatedString> const& protocols)
 {
-    auto underlying_websocket = m_websocket_client->connect(url, origin);
+    auto underlying_websocket = m_websocket_client->connect(url, origin, protocols);
     if (!underlying_websocket)
         return {};
     return WebSocketClientSocketAdapter::create(underlying_websocket.release_nonnull());

Userland/Libraries/LibWebView/WebSocketClientAdapter.h

@@ -26,6 +26,7 @@ public:
     virtual ~WebSocketClientSocketAdapter() override;
 
     virtual Web::WebSockets::WebSocket::ReadyState ready_state() override;
+    virtual DeprecatedString subprotocol_in_use() override;
 
     virtual void send(ByteBuffer binary_or_text_message, bool is_text) override;
     virtual void send(StringView text_message) override;
@@ -43,7 +44,7 @@ public:
 
     virtual ~WebSocketClientManagerAdapter() override;
 
-    virtual RefPtr<Web::WebSockets::WebSocketClientSocket> connect(const AK::URL&, DeprecatedString const& origin) override;
+    virtual RefPtr<Web::WebSockets::WebSocketClientSocket> connect(const AK::URL&, DeprecatedString const& origin, Vector<DeprecatedString> const& protocols) override;
 
 private:
     WebSocketClientManagerAdapter(NonnullRefPtr<Protocol::WebSocketClient>);

Userland/Services/WebSocket/ConnectionFromClient.cpp

@@ -75,6 +75,15 @@ Messages::WebSocketServer::ReadyStateResponse ConnectionFromClient::ready_state(
     return (u32)ReadyState::Closed;
 }
 
+Messages::WebSocketServer::SubprotocolInUseResponse ConnectionFromClient::subprotocol_in_use(i32 connection_id)
+{
+    RefPtr<WebSocket> connection = m_connections.get(connection_id).value_or({});
+    if (connection) {
+        return connection->subprotocol_in_use();
+    }
+    return DeprecatedString::empty();
+}
+
 void ConnectionFromClient::send(i32 connection_id, bool is_text, ByteBuffer const& data)
 {
     RefPtr<WebSocket> connection = m_connections.get(connection_id).value_or({});

Userland/Services/WebSocket/ConnectionFromClient.h

@@ -28,6 +28,7 @@ private:
 
     virtual Messages::WebSocketServer::ConnectResponse connect(URL const&, DeprecatedString const&, Vector<DeprecatedString> const&, Vector<DeprecatedString> const&, IPC::Dictionary const&) override;
     virtual Messages::WebSocketServer::ReadyStateResponse ready_state(i32) override;
+    virtual Messages::WebSocketServer::SubprotocolInUseResponse subprotocol_in_use(i32) override;
     virtual void send(i32, bool, ByteBuffer const&) override;
     virtual void close(i32, u16, DeprecatedString const&) override;
     virtual Messages::WebSocketServer::SetCertificateResponse set_certificate(i32, DeprecatedString const&, DeprecatedString const&) override;

Userland/Services/WebSocket/WebSocketServer.ipc

@@ -5,6 +5,7 @@ endpoint WebSocketServer
     // Connection API
     connect(URL url, DeprecatedString origin, Vector<DeprecatedString> protocols, Vector<DeprecatedString> extensions, IPC::Dictionary additional_request_headers) => (i32 connection_id)
     ready_state(i32 connection_id) => (u32 ready_state)
+    subprotocol_in_use(i32 connection_id) => (DeprecatedString subprotocol_in_use)
     send(i32 connection_id, bool is_text, ByteBuffer data) =|
     close(i32 connection_id, u16 code, DeprecatedString reason) =|
 

Userland/Utilities/headless-browser.cpp

@@ -592,6 +592,11 @@ public:
             VERIFY_NOT_REACHED();
         }
 
+        virtual DeprecatedString subprotocol_in_use() override
+        {
+            return m_websocket->subprotocol_in_use();
+        }
+
         virtual void send(ByteBuffer binary_or_text_message, bool is_text) override
         {
             m_websocket->send(WebSocket::Message(binary_or_text_message, is_text));
@@ -661,10 +666,11 @@ public:
 
     virtual ~HeadlessWebSocketClientManager() override { }
 
-    virtual RefPtr<Web::WebSockets::WebSocketClientSocket> connect(AK::URL const& url, DeprecatedString const& origin) override
+    virtual RefPtr<Web::WebSockets::WebSocketClientSocket> connect(AK::URL const& url, DeprecatedString const& origin, Vector<DeprecatedString> const& protocols) override
     {
         WebSocket::ConnectionInfo connection_info(url);
         connection_info.set_origin(origin);
+        connection_info.set_protocols(protocols);
 
         auto connection = HeadlessWebSocket::create(WebSocket::WebSocket::create(move(connection_info)));
         return connection;